I'm just going to spitball my thoughts here...
Stay away from those corner store used car lots. The used car salesman has a reputation for a reason. Big box car dealerships have scale and a reputation to protect so they're a much better bet. Also keep an eye on the salesman, vast majority of them are good people that want to get you into a good car, but be warned that there's always going to be people that don't give a crap about you. I've never bought from an individual because frankly I don't trust people and like that a dealership has management chains you can go after if something does go wrong.
Leasing is generally considered a terrible idea unless you're a high mileage driver or buying a luxury car. Loosely speaking, if you lease for $100/month vs. finance for $175/month let's say $75 of that finance payment is equity ownership, the rest is interest. You're "throwing away" just as much money each month so the real difference is at the end of your term. Lease, you have nothing to show for it - in fact you owe money if you want to keep the car. If you finance you at least own the car outright and can keep driving (no payment!) or sell it for whatever, $10K, and turn that money over into a new term. Eventually you'll be buying that late model civic outright. Leasing will never allow you to own a vehicle outright.
Warranties are also a bit of a sham since if you buy a reliable late model car and only drive it for a year you're almost guaranteed that you'll never need to claim on it. Just keep the $600+ warranty cash and put it in an emergency account. That said I do understand the benefit of that peace of mind so it's more of a personal call. I'd be very, very informed about what voids a warranty though (can you change your own oil? can you get lube city to do it or does it have to be dealership? what if you miss the maintenance schedule by 100km?).
Late model cars are super reliable anyway. The days of clogged carburetors and burnt out cat's before 175,000 km's are long gone. I drove a 2004 honda accord for 7 years from 2008-2015 and the only money I had to spend on it was oil changes, brakes and tires, none of which warranty covers (that I know of). And I drove and maintained it like the stupid college student that I was.
If you decide to finance something, never do it for more than 4 years. A loose rule of thumb is that a 4 year term will keep the balance owing roughly in line with the value of the car, any longer than that and you can be HEAVILY underwater before you know it.
At the end of the term, selling a decent vehicle is actually not hard at all - its as simple as showing it to someone, having them give you money and sign a piece a paper. It's worth the effort to save potentially thousands of dollars, and if it's a cheap, reliable, efficient, well maintained car you'll have no trouble getting interest from buyers.